Sir Alex Ferguson crosses swords with Roy Keane for the first time tomorrow, claiming his former captain was the best player he ever signed.

The Manchester United chief paid tribute to rookie manager Keane, who is finding his first season as a Premier League boss a tough test at Sunderland. But Fergie, speaking ahead of the Black Cats' visit to Old Trafford, raved: "In terms of ability, Roy wasn't the best player. But in terms of influence, he was.

"Certain people do well in life because of a real determination, a fire in their stomach that gets them somewhere.